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A towed pinger locator is a water-borne device used to locate the sonar "ping" from the underwater locator beacon which is fitted to the Cockpit Voice Recorders and Flight Data Recorders installed in commercial airliners.〔(【引用サイトリンク】url=http://timedotcom.files.wordpress.com/2014/03/tpl-25_specsheet.pdf )〕 They can locate pingers at depths of up to underwater. The locator is mounted in a hydrodynamic shell, or "tow fish", connected by winch behind a surface vessel across the search area. The locator listens for the sound emanating from the beacon or "pinger". Once located, the beacon and its attached recorders can be retrieved by divers, submersibles or remotely operated vehicle (ROV), depending on depth. A model currently used by the United States Navy is the TPL-25, which has a weight of and a length of ; it is generally towed at .〔 Most beacons transmit a pulse once a second at 37.5 kHz.〔 The hydrophone must be positioned below the thermocline layer which reflects sounds, either back to the surface or back to the ocean floor. Since the pinger signal is relatively weak, the hydrophone must be within about one nautical mile () to detect it. The hydrophone is typically deployed about above the ocean floor, where it can scan a swath approximately wide, on a flat, level surface. == See also == * Flight recorder * Distress radio beacon * Air France Flight 447 * Korean Air Lines Flight 007 * List of unrecovered flight recorders * Malaysia Airlines Flight 370 * Towed array sonar 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Towed pinger locator」の詳細全文を読む スポンサード リンク
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